The Innovative, Mysterious Alligator

Four months after the Monitor sank there, the Graveyard of the Atlantic pulled another victim down into its murky depths—the U.S. Navy's first submarine.

On a storm-tossed sea, a ship fights for her life on 2 April 1863. The crew works furiously at the pumps, but the sea will eventually win over muscle and machines; it is only a matter of time. A desperate conference between the ship's captain and the commander of a small vessel under tow results in the decision to save one ship by sacrificing the other. It is not an easy choice, for a major fleet awaits their arrival with this secret weapon. The last line is cut, and as the towing ship focuses on her own survival, the U.S. Navy's first submarine, the Alligator , is left to fend for herself in the raging waves off Cape Hatteras.

The story of the Alligator begins 10 August 1832 off the coast of France. There, before an assembly of officials, Brutus Villeroi, a self-styled civil engineer, demonstrated his invention: a human-powered "fish boat," 10 feet 6 inches in length and 3 feet 7 inches at her widest diameter. Before the witnesses and with Villeroi and two crewmen on board, the craft submerged, maneuvered, resurfaced, and returned to the shore. The demonstration, during which the crew collected shells from the seafloor, lasted an hour, and the boat reached a depth of 20 feet. Surviving accounts do not describe the craft's means of propulsion, although sketches made in 1837 show three pairs of duck-foot paddles. The boat also featured watertight sleeves into which the operator could insert his arms to secure a line to objects outside the hull while submerged. It was noted that the fish boat had both salvage and military applications.

Over the next quarter century, Villeroi gave at least two other demonstrations of submersible craft, and the inventor claimed that during the Crimean War the Russians had approached him about using one of his submarines against the allied fleet. This may have involved a larger boat, as Villeroi later claimed to have once built a vessel measuring 19 feet. In 1856 the French inventor moved to America, settling in Philadelphia and ennobling himself by adding the preposition "de" before his surname. There are hints, but no proof, that he brought a submarine with him. Within a few years, however, he began work on a new and larger boat, which was completed in early 1859.

Dubbed the Alligator Junior by researchers, the submarine was 35 feet long and 3.5 feet wide, built of boiler iron, and described as "perfectly round, like a fish" in cross-section. 1 Twin rows of deadlights provided light for the 12-man crew. Large rubber bladders served as ballast tanks, and a 3-foot propeller drove the boat. The submarine sported a rudder and bow planes - both controlled from a station beneath the small conning tower, whose portholes provided an external view. Once on the bottom, a conical iron anchor kept the Junior in place, resting on her stern with the lighter bow angled upward. A hatch in the bottom of the hull allowed salvage divers to exit and re-enter the vessel.

Unique among mid-century submersibles was the sub's air-purifying system. Although Villeroi kept the details secret, he would use a similar device in the Alligator . Spent air was pumped into a tank filled with limewater. 2 Calcium in the limewater absorbed the carbon dioxide in the air, which was then pumped out of the tank. The rudimentary system allowed dives of several hours.

Within a week of the attack on Fort Sumter, Villeroi offered his vessel to the U.S. Navy. Soon rumors were rife that the Confederates were building an ironclad warship on the hulk of the U.S. frigate Merrimack , and nobody was quite certain how to deal with the threat. The Navy preferred to counter with its own ironclad and requested construction that resulted in the Monitor , New Ironsides , and Galena . But why not also try a submarine ? Officers at the Philadelphia Navy Yard told Villeroi to begin construction of a larger version of the Junior , to measure 47 feet long.

Ostensibly for increasing maneuverability but at the expense of speed, a set of hinged oars was installed as propulsion and the screw propeller dispensed with. This design proved less than satisfactory. Longitudinal stability was by means of two buoyancy chambers, which were deployed upward on chains from centerline tube housings.

Whereas other contemporary submarines used external means for delivering explosives, Villeroi's craft had a lockout chamber, and her crew would include a diver. Maneuvering a torpedo (mine) through a small hatch in the bottom of the bow, the diver was to place it on target, return to the submarine, and detonate the explosive electrically via wires. Current was supplied by a bank of batteries stored within the boat. The method was safer than using a timer.

The Alligator , however, suffered from poor timing throughout her brief history. Construction delays were common, mostly occasioned by the unusual nature of the vessel as well as the bristly personality of her inventor, who was a bit of a scoundrel. The Navy eventually cut him out of the building process, and the boat was not launched until May 1862 - two months after the Merrimack , renamed the CSS Virginia , dueled with the Monitor at the Battle of Hampton Roads. The sub's whole reason for being seemed to vanish when the Confederate ironclad was scuttled on 11 May.

After Brutus de Villeroi's forced departure from the scene, the Navy selected Samuel Eakins, an expert diver with explosives experience, to oversee the Alligator project. Eakins, however, struggled to complete the boat and train a crew in preparation for a new and urgent mission to hasten a Union advance on Richmond. On 13 June 1862, the U.S. Navy officially accepted the boat into service and became the first navy in the world to have an operational submarine in its ship inventory. The "submarine propeller," as she was then referred to within the Navy, was towed to the James River in late June to try to blow up obstructions below Drewry's Bluff and destroy a railroad bridge over the Appomattox River near Petersburg. But the rivers were too shallow in both locations to allow the submarine to operate safely. Realizing that the boat was more in danger of being captured by Confederate forces than useful, the local naval commander, Commander John Rogers, ordered her out of the combat zone.

The Alligator was towed to the Washington Navy Yard, where a commissioned naval officer, Lieutenant Thomas O. Selfridge, and Navy crew were assigned to her. While testing the boat in the Potomac, Lieutenant Selfridge, who did not understand how to properly use the ballast tanks, managed to stand the Alligator on her stern. His report was predictably damning, and his request for reassignment immediately granted. The Navy again turned to Sam Eakins, appointing him acting master and instructing him to remove the boat's oars and refit her with a screw propeller. That was accomplished over the fall and winter of 1862. The more efficient screw allowed Eakins to halve the crew to only eight men, and it doubled the submarine's speed to four knots.

By 1863, the Alligator had a new assignment: Remove obstructions in Charleston Harbor in advance of an attack by ironclads of the blockading fleet. Although the Northern public believed the Navy's iron warships capable of anything, naval officers knew better; getting hung up beneath the guns of Fort Sumter and the harbor's other Rebel batteries would invite destruction. The job was tailor-made for the Alligator .

In preparation for the assignment, Eakins may have made one additional change to the boat, for which there is only circumstantial—but telling—evidence. In a letter written only weeks before his departure for Charleston, he claimed to have realized that Villeroi had allowed for a second means of using the submarine. Eakins does not specify what that was, but said it would allow him to make the attack—that is, place the mines—personally. The final crew roster does not mention a diver, and Eakins specifically stated that his idea would allow him to dispense with any diver. That suggests some means by which he, as captain, could place the charges without exiting his vessel.

A clue may survive in an 1865 sketch by an anonymous Navy officer showing what appears to be the upper half of a diving suit attached to the top hatch of a small submarine. In the drawing, the arms are shown as flexible—perhaps indicating they are rubber sleeves and that the rest of the suit is inflexible, made of bronze or iron. It is reminiscent of Villeroi's original fish boat with her watertight sleeves that allowed her operator to extend his arms beyond the hull. Was this Eakins' idea, and was it incorporated into the Alligator ? Such an arrangement—with a torpedo strapped into a cradle near the hatch, attached to a grappling hook, and with "galvanic wire" ready to connect—would have made the submarine a much more lethal (and maneuverable) warship.

Ordered to Port Royal, the Alligator set sail under tow of the screw gunboat USS Sumpter on 29 March. Eakins and his crew berthed on board the surface ship. On 2 April off Cape Hatteras, the wind picked up and blew a gale from the northwest. When it shifted to the southwest and increased to "a heavy gale," the Alligator continued to tow smoothly. But by 1700 the seas had increased and the Sumpter was taking water. The sub began "towing hard," and one of the two hawsers attached to her parted so that she began to "steer wildly." A hurried council of officers, including Eakins, agreed that cutting the Alligator loose was the only way to save the Sumpter, whose engines were already laboring with two feet of water in the hold. At 1800, that was done. The submarine was lost at sea. The ironclad attack she was intended to facilitate proceeded on schedule, was stymied by obstructions, and failed.

Despite the Alligator 's apparent lack of success, her story is peppered with firsts. Not only was she the first submarine accepted into the U.S. Navy and the first of the Civil War, she was also the first deployed to a combat zone and the first to be refit in a navy yard. Through bad timing and circumstances her potential was never tested in combat. But that does not detract from the bravery of her crews, civilian and military, and the advances she represented in a time of technological flux, when the Navy led the way in the transition from the Age of Sail to the Age of Iron and Steam.

1. Villeroi did not name his boats, and the Navy originally referred to the later vessel as "the submarine propeller." But a newspaper reporter who watched the green-painted warship pushed along the surface by her banks of oars gave her a name: "It looks like an alligator!" Being smaller, her predecessor was christened by researchers the Alligator Junior .

2. Created by the immersion of crushed seashells, lime, or chalk - all rich in calcium.

Still Eluding Searchers

By David Hall

Using a variety of remote sensing instruments, researchers from the National Oceanic and Atmospheric Administration (NOAA), the Office of Naval Research (ONR), and East Carolina University conducted the first comprehensive hunt for the Civil War vessel Alligator , the U.S. Navy's first submarine, in August 2004.

The search took place off Cape Hatteras, North Carolina, where the green sub was lost during a fierce storm in 1863. Operating from the ONR's 108-foot YP-679 "Afloat Lab," a former Navy training ship used for outreach, education, and research, the 10-person expedition team used sidescan sonar, a magnetometer, and a remotely operated vehicle to comb more than 50 nautical miles of the seafloor for the elusive boat.

NOAA, with support from the ONR, continued the hunt for the Alligator in September 2005. During that mission, researchers deployed a magnetometer and autonomous underwater vehicle to investigate targets identified during the August 2004 NOAA-ONR survey and a NOAA survey of opportunity in May 2005.

While searches for the Alligator have so far proved inconclusive, interest in her continues ashore in libraries, classrooms, studios, workshops, and beyond thanks to a dedicated team of historians, naval experts, engineers, modelers, artists, teachers, and students who have joined forces to uncover the elusive submarine's secrets. Simultaneously, researchers are probing waters near Philadelphia in the area of inventor Brutus de Villeroi's shipyard for indications of the 1859 prototype submarine, the Alligator Junior . Intriguing magnetometer data gathered in 2009 are currently being analyzed by NOAA and will hopefully lead to actual excavation.

Mr. Hall is a public information officer with the National Oceanic and Atmospheric Administration.